Caesar cipherCaesar cipher, is one of the simplest and most widely known encryption techniques.
The transformation can be represented by aligning two alphabets,
the cipher alphabet is the plain alphabet rotated left or right by some number of positions.
When encrypting, a person looks up each letter of the message in the 'plain'
line and writes down the corresponding letter in the 'cipher' line. Deciphering is done in reverse.
The encryption can also be represented using modular arithmetic
by first transforming the letters into numbers, according to the scheme, A = 0, B = 1,..., Z = 25.
Encryption of a letter x by a shift n can be described mathematically as
Plaintext: bobbling

cipher variations:

cpccmjoh

dqddnkpi

ereeolqj

fsffpmrk

gtggqnsl

huhhrotm

iviispun

jwjjtqvo

kxkkurwp

lyllvsxq

mzmmwtyr

nannxuzs

obooyvat

pcppzwbu

qdqqaxcv

rerrbydw

sfssczex

tgttdafy

uhuuebgz

vivvfcha

wjwwgdib

xkxxhejc

ylyyifkd

zmzzjgle

anaakhmf

Decryption is performed similarly,
(There are different definitions for the modulo operation.
In the above, the result is in the range 0...25. I.e., if x+n or x-n are not in the range 0...25,
we have to subtract or add 26.)
Read more ...Atbash CipherAtbash is an ancient encryption system created in the Middle East.
It was originally used in the Hebrew language.
The Atbash cipher is a simple substitution cipher that relies on
transposing all the letters in the alphabet such that the resulting alphabet is backwards.
The first letter is replaced with the last letter, the second with the second-last, and so on.
An example plaintext to ciphertext using Atbash:

Baconian CipherTo encode a message, each letter of the plaintext is replaced by a group of five of the letters 'A' or 'B'.
This replacement is done according to the alphabet of the Baconian cipher, shown below.

Affine CipherIn the affine cipher the letters of an alphabet of size m are first mapped to the integers
in the range 0..m - 1. It then uses modular arithmetic to transform the integer that each plaintext
letter corresponds to into another integer that correspond to a ciphertext letter.
The encryption function for a single letter is
where modulus m is the size of the alphabet and a and b are the key of the cipher.
The value a must be chosen such that a and m are coprime.Considering the specific case of encrypting messages in English (i.e. m = 26),
there are a total of 286 non-trivial affine ciphers, not counting the 26 trivial Caesar ciphers.
This number comes from the fact there are 12 numbers that are coprime with 26 that are less than 26
(these are the possible values of a). Each value of a can have 26 different addition shifts (the b value)
; therefore, there are 12*26 or 312 possible keys.Plaintext: bobbling

cipher variations:

cpccmjoh

ereeizot

gtggepof

iviiafor

kxkkwvod

mzmmslop

qdqqkron

sfssghoz

uhuucxol

wjwwynox

ylyyudoj

anaaqtov

dqddnkpi

fsffjapu

huhhfqpg

jwjjbgps

lyllxwpe

nanntmpq

rerrlspo

tgtthipa

vivvdypm

xkxxzopy

zmzzvepk

bobbrupw

ereeolqj

gtggkbqv

iviigrqh

kxkkchqt

mzmmyxqf

oboounqr

sfssmtqp

uhuuijqb

wjwwezqn

ylyyapqz

anaawfql

cpccsvqx

fsffpmrk

huhhlcrw

jwjjhsri

lylldiru

nannzyrg

pcppvors

tgttnurq

vivvjkrc

xkxxfaro

zmzzbqra

bobbxgrm

dqddtwry

gtggqnsl

iviimdsx

kxkkitsj

mzmmejsv

obooazsh

qdqqwpst

uhuuovsr

wjwwklsd

ylyygbsp

anaacrsb

cpccyhsn

ereeuxsz

huhhrotm

jwjjnety

lylljutk

nannfktw

pcppbati

rerrxqtu

vivvpwts

xkxxlmte

zmzzhctq

bobbdstc

dqddzito

fsffvyta

iviispun

kxkkofuz

mzmmkvul

obooglux

qdqqcbuj

sfssyruv

wjwwqxut

ylyymnuf

anaaidur

cpccetud

ereeajup

gtggwzub

jwjjtqvo

lyllpgva

nannlwvm

pcpphmvy

rerrdcvk

tgttzsvw

xkxxryvu

zmzznovg

bobbjevs

dqddfuve

fsffbkvq

huhhxavc

kxkkurwp

mzmmqhwb

oboomxwn

qdqqinwz

sfssedwl

uhuuatwx

ylyyszwv

anaaopwh

cpcckfwt

ereegvwf

gtggclwr

iviiybwd

lyllvsxq

nannrixc

pcppnyxo

rerrjoxa

tgttfexm

vivvbuxy

zmzztaxw

bobbpqxi

dqddlgxu

fsffhwxg

huhhdmxs

jwjjzcxe

mzmmwtyr

oboosjyd

qdqqozyp

sfsskpyb

uhuugfyn

wjwwcvyz

anaaubyx

cpccqryj

ereemhyv

gtggixyh

iviienyt

kxkkadyf

nannxuzs

pcpptkze

rerrpazq

tgttlqzc

vivvhgzo

xkxxdwza

bobbvczy

dqddrszk

fsffnizw

huhhjyzi

jwjjfozu

lyllbezg

obooyvat

qdqqulaf

sfssqbar

uhuumrad

wjwwihap

ylyyexab

cpccwdaz

ereestal

gtggojax

iviikzaj

kxkkgpav

mzmmcfah

pcppzwbu

rerrvmbg

tgttrcbs

vivvnsbe

xkxxjibq

zmzzfybc

dqddxeba

fsfftubm

huhhpkby

jwjjlabk

lyllhqbw

nanndgbi

qdqqaxcv

sfsswnch

uhuusdct

wjwwotcf

ylyykjcr

anaagzcd

ereeyfcb

gtgguvcn

iviiqlcz

kxkkmbcl

mzmmircx

obooehcj

rerrbydw

tgttxodi

vivvtedu

xkxxpudg

zmzzlkds

bobbhade

fsffzgdc

huhhvwdo

jwjjrmda

lyllncdm

nannjsdy

pcppfidk

sfssczex

uhuuypej

wjwwufev

ylyyqveh

anaamlet

cpccibef

gtggahed

iviiwxep

kxkksneb

mzmmoden

obooktez

qdqqgjel

tgttdafy

vivvzqfk

xkxxvgfw

zmzzrwfi

bobbnmfu

dqddjcfg

huhhbife

jwjjxyfq

lylltofc

nannpefo

pcpplufa

rerrhkfm

uhuuebgz

wjwwargl

ylyywhgx

anaasxgj

cpccongv

ereekdgh

iviicjgf

kxkkyzgr

mzmmupgd

obooqfgp

qdqqmvgb

sfssilgn

vivvfcha

xkxxbshm

zmzzxihy

bobbtyhk

dqddpohw

fsfflehi

jwjjdkhg

lyllzahs

nannvqhe

pcpprghq

rerrnwhc

tgttjmho

wjwwgdib

ylyyctin

anaayjiz

cpccuzil

ereeqpix

gtggmfij

kxkkelih

mzmmabit

oboowrif

qdqqshir

sfssoxid

uhuuknip

xkxxhejc

zmzzdujo

bobbzkja

dqddvajm

fsffrqjy

huhhngjk

lyllfmji

nannbcju

pcppxsjg

rerrtijs

tgttpyje

vivvlojq

ylyyifkd

anaaevkp

cpccalkb

ereewbkn

gtggsrkz

iviiohkl

mzmmgnkj

oboocdkv

qdqqytkh

sfssujkt

uhuuqzkf

wjwwmpkr

zmzzjgle

bobbfwlq

dqddbmlc

fsffxclo

huhhtsla

jwjjpilm

nannholk

pcppdelw

rerrzuli

tgttvklu

vivvralg

xkxxnqls

anaakhmf

cpccgxmr

ereecnmd

gtggydmp

iviiutmb

kxkkqjmn

obooipml

qdqqefmx

sfssavmj

uhuuwlmv

wjwwsbmh

ylyyormt

bobbling

dqddhyns

fsffdone

huhhzenq

jwjjvunc

lyllrkno

pcppjqnm

rerrfgny

tgttbwnk

vivvxmnw

xkxxtcni

zmzzpsnu

The decryption function iswhere a - 1 is the modular multiplicative inverse of a modulo m. I.e., it satisfies the equationThe multiplicative inverse of a only exists if a and m are coprime.
Hence without the restriction on a decryption might not be possible.
It can be shown as follows that decryption function is the inverse of the encryption function,Read more ...

ROT13 CipherApplying ROT13 to a piece of text merely requires examining its alphabetic
characters and replacing each one by the letter 13 places further along in the alphabet,
wrapping back to the beginning if necessary. A becomes N, B becomes O, and so on up to M,
which becomes Z, then the sequence continues at the beginning of the alphabet: N becomes A,
O becomes B, and so on to Z, which becomes M. Only those letters which occur in the English
alphabet are affected; numbers, symbols, whitespace, and all other characters are left unchanged.
Because there are 26 letters in the English alphabet and 26 = 2 * 13, the ROT13 function is its own inverse:

Polybius SquareA Polybius Square is a table that allows someone to translate letters into numbers.
To give a small level of encryption, this table can be randomized and shared with the recipient.
In order to fit the 26 letters of the alphabet into the 25 spots created by the table, the letters
i and j are usually combined.

1

2

3

4

5

1

A

B

C

D

E

2

F

G

H

I/J

K

3

L

M

N

O

P

4

Q

R

S

T

U

5

V

W

X

Y

Z

Basic Form:

Plain:

bobbling

Cipher:

2143212113423322

Extended Methods:Method #1

Plaintext: bobbling

method variations:

gtggqosm

mymmvtxr

rdrraycw

wiwwfdhb

Method #2Bifid cipherThe message is converted to its coordinates in the usual manner, but they are written vertically beneath:

b o b b l i n g
2 4 2 2 1 4 3 2
1 3 1 1 3 2 3 2

They are then read out in rows:
2422143213113232Then divided up into pairs again, and the pairs turned back into letters using the square:

Permutation CipherIn classical cryptography, a permutation cipher is a transposition cipher in which the key is a permutation.
To apply a cipher, a random permutation of size E is generated (the larger the value of E the more secure the cipher).
The plaintext is then broken into segments of size E and the letters within that segment are permuted according to
this key.
In theory, any transposition cipher can be viewed as a permutation cipher where E is equal to the
length of the plaintext; this is too cumbersome a generalisation to use in actual practice, however.
The idea behind a permutation cipher is to keep the plaintext characters unchanged,
butalter their positions by rearrangement using a permutation
This cipher is defined as:Let m be a positive integer, and K consist of all permutations of {1,...,m}For a key (permutation) , define:
The encryption function The decryption function A small example, assuming m = 6, and the key is the permutation
:The first row is the value of i,
and the second row is the corresponding value of (i)The inverse permutation, is constructed by interchanging the two rows,
andrearranging the columns so that the first row is in increasing order, Therefore, is:
Total variation formula: e = 2,718281828 , n - plaintext length